"The
New Jim Crow" by Michelle Alexander, a law professor and
civil rights advocate, explores the idea that the "war on drugs"
has unfairly led to the mass incarceration of non-violent
black and Latino males as well as their treatment as
second-class citizens once they get out of prison.

Zuckerberg read it earlier this year as part of his
"Year of Books" challenge, and decided to visit the Marin
County prison with his wife Priscilla Chan to see first-hand what
prison conditions are like by talking to inmates and staff.

Unlike many prisons in the US, San Quentin runs programs to teach
inmates skills, like coding, that will help them find jobs and
has earned "one of the best track records of people not returning
to jail" after they are released.

"Making our criminal justice system fairer and more effective is
a huge challenge for our country," Zuckerberg writes. "I'm going
to keep learning about this topic, but some things are already
clear. We can't jail our way to a just society, and our current
system isn't working."